Lead author Philip McCarthy, MD:“With this complete and mature data from three large multinational studies, we now have clear evidence that ongoing maintenance therapy with lenalidomide can prevent disease progression and extend survival in patients with myeloma who’ve received a stem cell transplant. … Lenalidomide maintenance can be considered a new standard of care following primary induction therapy and transplant for transplant-eligible patients. … What we need to know for the future is how long patients need to stay on maintenance, which patients benefit the most from maintenance, and which high-risk patients will need a different approach to long-term disease control.”

Maintenance therapy with lenalidomide after autologous hematopoietic cell transplantation (AHCT) prolonged overall survival (OS) in patients with newly diagnosed myeloma compared with placebo or observation only, according to a meta-analysis of three large randomized clinical trials published in the Journal of Clinical Oncology.

Previous trials have reported that lenalidomide improves progression-free survival (PFS), but this is the first analysis to demonstrate the benefits of lenalidomide maintenance on OS. The results of the analysis served as part of the U.S. Food and Drug Administration’s and European Medicines Agency’s approval of lenalidomide as maintenance therapy earlier this year, noted the authors, led by Philip McCarthy, MD, from Roswell Park Cancer Institute in Buffalo, New York.

The authors reported that median PFS was more than two times longer for patients who received lenalidomide: 52.8 months versus 23.5 months (hazard ratio [HR] = 0.48; 95% CI 0.41-0.55; p value not provided).

At a median follow-up of 79.5 months for all surviving patients, the median OS had not been reached in the lenalidomide maintenance group, but it was 86.0 months for the placebo or observation group (HR=0.75; 95% CI 0.63-0.90; p=0.001).

However, the researchers added, lenalidomide maintenance appeared to be associated with an increased incidence of secondary primary malignancy before disease progression compared with placebo or observation (5.3% vs. 0.8% for hematologic and 5.8% vs. 2.0% for solid malignancies; p values not reported).

The study is limited by a lack of adequate cytogenetic analyses in the CALGB study and information about the role of minimal residual disease. “Many patients did not have adequate staging data at diagnosis, which includes lactate dehydrogenase levels and fluorescence in situ hybridization analysis,” Dr. McCarthy said, adding that future studies “will be examining the role of minimal residual disease detection, as well as cytogenetic risk and staging in myeloma patients who receive maintenance therapy.”